Immediately after takeoff; we received a master caution with the following EICAS messages: hydraulic pump fail a; hydraulic fluid low a; hydraulic ptu fail. At the same time; we noticed that the main gear had retracted; but the nose wheel was extended with a green light. We executed the checklist for the hydraulic pump fail a and diverted to [nearest suitable airport]. We notified company. We asked for crash equipment to stand by. After using the emergency gear extension per the checklist; we executed the ILS and stopped on the runway using the emergency brake. [We were] towed to the service center where they found a ruptured hydraulic line in the nose wheel bay. One important problem to note is the difficulty that we had getting in touch with the company. When we first notified company it was via the [VHF] frequency. We were asked to call in on the satellite phone; so that the flight district's officer could be conferenced in. On my first call; I dialed the dispatch hotline via the number on the sticker on the phone. I called this number twice and did not get an answer (phone rang). Second; I tried the normal number on the phone sticker. I dialed this number twice and got a recording both times that said that the number was out of service. At this point; I told the first officer what was happening and he dialed the 800 number to dispatch from memory and was able to get through. Suggestions: thorough inspection of hydraulic lines. A cessna mechanic said that this was the 'weak link' in the system. Perhaps these lines should be replaced more often. Check of phone system at dispatch. Stickers in airplanes with phone numbers might need to be replaced.

Title: CE-750 First Officer reported loss of hydraulic system A. They declared an emergency and diverted to the nearest suitable airport; where a hydraulic line failure was diagnosed.

Narrative: Immediately after takeoff; we received a master caution with the following EICAS messages: Hydraulic pump fail A; hydraulic fluid low A; hydraulic PTU fail. At the same time; we noticed that the main gear had retracted; but the nose wheel was extended with a green light. We executed the checklist for the Hydraulic Pump Fail A and diverted to [nearest suitable airport]. We notified company. We asked for crash equipment to stand by. After using the emergency gear extension per the checklist; we executed the ILS and stopped on the runway using the emergency brake. [We were] towed to the service center where they found a ruptured hydraulic line in the nose wheel bay. One important problem to note is the difficulty that we had getting in touch with the company. When we first notified company it was via the [VHF] frequency. We were asked to call in on the satellite phone; so that the Flight District's Officer could be conferenced in. On my first call; I dialed the Dispatch hotline via the number on the sticker on the phone. I called this number twice and did not get an answer (phone rang). Second; I tried the normal number on the phone sticker. I dialed this number twice and got a recording both times that said that the number was out of service. At this point; I told the First Officer what was happening and he dialed the 800 number to Dispatch from memory and was able to get through. Suggestions: Thorough inspection of hydraulic lines. A Cessna Mechanic said that this was the 'weak link' in the system. Perhaps these lines should be replaced more often. Check of phone system at Dispatch. Stickers in airplanes with phone numbers might need to be replaced.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.